Organic silicone synthesis belongs to the category of fine chemicals, with a long synthetic route and strict process control in the monomer synthesis section. The synthesis of organic silicon monomers from raw materials such as methanol, hydrogen chloride and silicon powder can be divided into five segments.
Monochloromethane (b.p.-24°C) was synthesized at a pressure of 0.4 MPa and a zinc chloride catalyst.
The 2nd segment: Synthesis of silicone monomers
In this section, chloromethane gas carrying silicon powder (60-160 mesh) enters into the fluidized laver and the organosilicon monomer is synthesized at 300° C., 0.2-0.3 MPa pressure, and CuCl catalyst.
The 3rd segment: Monomer fractionation
After 11 towers and more than 60 auxiliary equipments, the monomers from the synthesis section are rectified and separated to Dimethyl monomer, Trimethyl monomer, Monomethyl monomer, Hydrogen monomer and High-boiler etc. are separated according to the purity requirements.
The 4th segment: Monomer hydrolysis
Dimethyl monomer hydrolyzes to linear monomer and ring monomer (Dn) with the presence of hydrochloric acid medium.
Tip: n = 3, 4, 5, etc. the tetracyclic body, octamethylcyclotetrasiloxane(D4), is the typical one.
The 5th segment: Pyrolysis of Linear Monomers
The linear, which account for 60% of the hydrolyzed yield, were further lysed into ring (Dn).